Virtually all countries within the European continent have been perpetrators of colonialism and genocide in the past 4 centuries, several in the last 90 years, and a few in the last 20 years. It is a banal observation.

The reason why the string "tiananmen" is so frequently invoked is that it is a convenient litmus test for censorship/alignment/whatever-your-preferred-term by applications that must meet Chinese government regulations. There is no equivalent universal string that will cause applications to immediately error out in applications hosted in the EU or the US. Of course each US-hosted application has its own prohibited phrases or topics, but it is simple and convenient to use a single string for output filtering when testing.